26: bacterial composition Flashcards
Why can we consume antibiotic bacteria?
selective toxicity, antimicrobial compounds selectively inhibit microbe but not host, achieved by targeting conserved bacterial component
What do the cell membrane targets do?
antimicrobial peptides, charge attract membrane, cause pores to lysis, ion leak, PMF disruption
-> can be taken topically
What do metabolic inhibitors do?
inhibit nucleotide biosynthesis in human DNA, bacterial folic cells are different than human folic acid, antibiotics selectively block this
How do RNA/DNA polymerase inhibitors work?
enzymes different enough for selective inhibition
What do B-lactam antibiotics do?
targets PG which is exclusive to bacteria, mimics D-alanine in PG cross linking, and binds active site of PBP to form a covalent bond
-> can’t bind PG peptide bridges
What does bactericidal mean?
kill bacteria when exposed to them?
What differentiates narrow vs. Broad spectrum?
how well they target bacteria
Which gram morphology is more susceptible to antibiotics?
G+ because only has one PG layer whereas gram negative has two
What is the MIC?
minimum inhibitory concentration (MIC), smallest concentration of the compound that completely inhibits growth
Which gram morphology has the lowest MIC?
gram positive has the lower mic because it is more susceptible bc of only one PG layer
How does a penicillin allergy occur?
body develop foreign peptide antibody that sense when we have a small molecule bound. SO when penicillin binds PBPs, are body makes antigens for it
What is a mast cell?
A cell with an antibody on the membrane that can sense antigens and release histamine
What are broad spectrum antibiotics?
kill all bacteria, target both harmful and beneficial, can cause C.dificile in GI tract
what is an aminoglycoside
binds 16s rRNA of bacteria, associated with negative side effects because of endosymbiotic theory, inhibits mitochndirla function
antibiotic resistance mechanism 1
prevent antibiotic entry, exporters can specificallyy bind antibiotics to pump them out and keep them away from target
